The proliferation and popularity of mobile radio and telephony applications has led to market demand for communication systems with low cost, low power, and small form-factor radio-frequency (RF) transceivers. As a result, recent research has focused on providing monolithic transceivers using low-cost complementary metal-oxide semiconductor (CMOS) technology. One aspect of research efforts has focused on providing an RF transceiver within a single integrated circuit (IC). The integration of transceiver circuits is not a trivial problem, as it must take into account the requirements of the transceiver's circuitry and the communication standards governing the transceiver's operation.
From the perspective of the transceiver's circuitry, RF transceivers typically include sensitive components susceptible to noise and interference with one another and with external sources. Integrating the transceiver's circuitry into one integrated circuit may exacerbate interference among the various blocks of the transceiver's circuitry. Moreover, communication standards governing RF transceiver operation outline a set of requirements for noise, inter-modulation, blocking performance, output power, and spectral emission of the transceiver. Unfortunately, no technique for addressing all of the above issues in high-performance RF receivers or transceivers, for example, RF transceivers used in cellular and telephony applications, has been developed. A need therefore exists for techniques of partitioning and integrating RF receivers or transceivers that would provide low-cost, low form-factor RF transceivers for high-performance applications, for example, in cellular handsets.
A further aspect of RF apparatus, such as RF transceivers and receivers, relates to the front-end circuitry of the RF apparatus. Typically, the front-end circuitry of modem RF apparatus includes a filter circuitry and a low-noise amplifier (LNA) circuitry. The output impedance of the filter circuitry often differs from the input impedance of the LNA circuitry. Proper transfer of signals between the filter circuitry an the LNA circuitry and the performance of the front-end circuitry, however, depends in part on the matching of the output impedance of the filter circuitry to the input impedance of the LNA circuitry. A need therefore exists for a matching network suitable for use in the front-end circuitry of modem RF apparatus, such as a cellular telephone handset chipset implemented in complementary metal oxide semiconductor (CMOS).